I was diagnosed 6 yrs ago, and felt the same relief you are feeling, but it was also a bit of a mad, sad, lonely time as well.
Your struggle with tiredness (or fatigue as it is better discribed), is something I suffer from terribly. My neurologist suugested I tried ‘Modafinil’ a couple of years ago, and it definitely helps, but it is not a cure.
It is a drug that is used to increase alertness, and helps with that mental fatigue completely overtakes me sometimes. It is mostly used for conditions like narcolepsy, and sometimes prescibed for shift workers.
My neurologist said that my GP would have to okay the presciption first, as it is not licenced for Ms in the UK, but it all went smoothly and I got the presciption.
I started on 100mg twice a day, but have had my presciption upped to 200mg twice a day. No eyebrows raised by my GP.
Like I mentioned earlier, it is not a cure, but it does help.
I really do understand what you’re descibing, It wasn’t until I was diagnosed with MS I even considered the difference between tiredness and fatigue, but it is, so very different. I still find the overwhelming feeling I get, really difficult to describe to others.
Modafinil will not help with your motor ability. You will still be unable to walk very far, and your legs will be rubbish, but you will be a tad more focussed and awake after taking it.
As I’ve mentioned, it is quite hard to get it prescribed these days, but talk to your neurologist and see if they can suggest it to your GP.
Good luck with all of it, and use these forums for some really sound advice, from the folk that know what you’re going through.